1. Technical Field
Example embodiments relate to aromatic enediyne derivatives, organic semiconductor thin films formed using such aromatic enediyne derivatives and methods of manufacturing such films, and electronic devices incorporating such organic semiconductor thin films and methods of manufacturing such devices, and, for example, to organic semiconductor thin films fabricated from such aromatic enediyne derivatives that exhibit improved chemical and electrical stability. The aromatic enediyne derivatives according to example embodiments may be applied to substrates via solution-based processes, for example, spin coating, and are suitable for application at or near room temperature to form a coating layer that, after thermal treatment, may form an organic semiconductor thin film on the substrate that may be used in forming a carrier transport layer in an electronic device incorporating such an organic semiconductor thin film.
2. Description of the Related Art
In general, flat display devices, for example, liquid crystal display devices or organic electroluminescent display devices, utilize various thin film transistors during operation. One basic thin film transistor construction comprises a gate electrode formed on a gate dielectric, source/drain electrodes, and a semiconducting channel region formed in a semiconducting material adjacent the gate dielectric and opposite the gate electrode. The conductivity of this semiconducting channel region is, in turn, controlled through operation of the gate electrode. The p-type or n-type semiconductor material forming the channel region serves as a conductive material when the gate electrode is in an “on” state to allow current to flow between the source and drain electrodes and serves as a resistive material when the gate electrode is in an “off” state to suppress leakage current between the source and drain electrodes. The “on” and “off” states of the transistor may correspond to two different voltages that may be alternatively applied to the gate electrode for controlling current flow between the source and drain electrodes.
Although a range of semiconductor materials may be used for forming thin film transistors, amorphous Si (a-Si) and polycrystalline Si (poly-Si) are widely used. As a result of recent trends toward larger areas, lower prices and/or improved flexibility of video displays, various efforts have been directed to manufacturing semiconductors using more flexible organic materials rather than the conventional, relatively expensive and/or rigid inorganic materials, which may require the use of higher-temperature vacuum and/or furnace processes in their formation.
Research into various lower molecular weight organic materials, for example, pentacene, for forming organic semiconductor films is presently ongoing. In this regard, the lower molecular weight organic materials, for example, pentacene, have been reported as having charge mobility in the range of 3.2 to 5.0 cm2/V-s or more and an excellent current on/off ratio. These materials, however, are known to have deficiencies including, for example, the expense associated with forming layers of such materials and difficulty forming a generally uniform layer across large areas of a substrate. These deficiencies are, to some degree, attributable to the need to use expensive vacuum deposition apparatus in forming thin films from these lower molecular weight organic materials and an associated difficulty in forming fine patterns.
Further, oligomeric organic semiconductors, for example, a soluble pentacene precursor, have been reported as suitable for application to a substrate and annealing at about 120 to 200° C. to produce an organic semiconducting layer having a charge mobility of about 0.1 cm2/V-s. In addition, other oligothiophene precursors capable of being applied to a substrate to produce an organic semiconducting layer having a charge mobility of 0.03 to 0.05 cm2/V-s and capable of being annealed at 180 to 200° C., have also been reported. However, such organic semiconductors may be chemically unstable during the subsequent processing necessary to complete the fabrication of a semiconductor device and are accordingly difficult to implement in an actual device manufacturing line. Moreover, results obtained by repeated current-electron sweeping for evaluating electrical stability tends to exhibit a lack of electrical stability that may result in both reduced gate threshold voltage, increased leakage currents and/or reduced reliability of the resulting devices.
Other organic compounds containing an acetylene groups and methods of manufacturing a thin film of such materials through a vacuum deposition process using the organic compound have also been reported. However, the organic compounds and the methods of manufacturing thin films from such organic compounds may require a vacuum deposition process in order to manufacture a thin film. Accordingly, the use of lower molecular weight compounds, for example, pentacene, may be expensive and generally unsuited for preparing organic semiconductor films over a large substrate area for cost-sensitive products.